The successful development of an organism requires that many functionally distinct yet interdependent organ systems develop, grow and function in concert with each other. However, mechanisms whereby the concerted development of variant systems is achieved remain largely unknown. The developing pancreas of the mouse Mus musculus provides a dynamic system in which to study autonomic nervous development during pancreas organogenesis. Several antibodies to specific neuron subtypes that innervate the pancreas have been identified, and techniques have been developed to provide a developmental description of pancreatic innervation at high resolution. The Pax4-Sonic Hedgehog transgenic line perturbs embryonic and neonatal endocrine development, providing a context in which to assay to what degree endocrine innervation is dependent upon proper islet formation. The RIP-cmyc(ER) mouse line has been identified as a model in which to assess the growth of autonomic neurons during large-scale apoptosis and regeneration of insulin producing endocrine cells in mature islets of Langerhans. Experiments in this research application are designed to describe neuroendocrine development during organogenesis and examine the effects of endocrine perturbation on pancreatic innervation.